1. Field of the Invention
The present invention pertains to a system and method for verifying that files obtained through digital data processing have acceptable characteristics.
The system and method are particularly useful for analyzing and assessing automatically the sonic quality of a large number of digital audio files and other similar files containing audiovisual programs.
2. Background of the Invention
Presently comparing a derivative digital version of a file to an original file is accomplished in one of two ways. If the files have the same format they could be compared directly, bit-by-bit. This type of comparison is useful in checking the quality of a simple data transmission device or checking a file that is a copy of another file. A bit-to-bit comparison is useful in such cases because the file being checked is expected to be identical to the original.
This type of comparison, however, is not practical for verifying files that have undergone extensive signal processing or other type of transformation since they are not substantially identical to the original files. For example, a digital audio file that has been compressed, watermarked, or derived in some other manner from an original audio file may still have a sonically acceptable quality even though the derivative file is substantially different from the original if a bit-to-bit comparison is used. Therefore, other techniques must be used for checking these types of files. One such technique is essentially a manual technique in the sense that it requires each derivative file to be checked individually. The manual technique requires derivative audio files to be verified by a specially trained audio engineer by listening to each digital file separately and using his subjective opinion to determine whether that file has acceptable audio quality. This technique is used to check various different types of digital files for recording entertainment and other similar content (e.g., audio, video, image, and multimedia). However, for the sake of clarity, in the present application the term ‘digital audio file’ is used to cover generically all other types of digital files as well, such as digital video files.
The manual technique has several problems. The first problem is that it must be performed in real time. That is, if a file contains an audio selection sixty minutes long, the audio technician must spend sixty minutes to listen to it. Accordingly, this technique is very slow and labor intensive. The second problem is that it is expensive since it requires trained and experienced audio engineers. The third problem is that, like with any other extended task performed manually and relying on subjective criteria, its accuracy and repeatability is inconsistent. For example, after listening to files for extended periods of time, the audio engineer may become fatigued and inattentive, and accordingly, he may reject some of the files, especially files that are on the borderline, which he may find acceptable at other times, and vice versa.
These problems clearly point to a need to automate the process of verifying derivative digital audio files. Such an automated process would be of value for many endeavors, but especially important for the entertainment industry.